Effects of suvorexant on sleep architecture and power spectral profile in patients with insomnia: analysis of pooled phase 3 data

Sleep Med. 2016 Mar;19:93-100. doi: 10.1016/j.sleep.2015.10.007. Epub 2015 Nov 10.


Background: The orexin receptor antagonist, suvorexant, is approved for treating insomnia at a maximum dose of 20 mg. We evaluated its effects on sleep architecture.

Methods: The analyses included pooled polysomnography data from two similar randomized, double-blind, placebo-controlled, 3-month trials evaluating two age-adjusted (non-elderly/elderly) dose regimes of 20/15 mg and 40/30 mg in 1482 patients with insomnia. Polysomnography was recorded at baseline and on three nights during the treatment: Night-1, Month-1, and Month-3. Effects on non-REM sleep stages 1 (N1), 2 (N2), 3 (N3)/slow wave sleep (SWS), and REM sleep were evaluated. A power spectral analysis of non-REM sleep was also performed.

Results: Suvorexant increased the time (in minutes) spent in all sleep stages compared with placebo. When suvorexant and placebo were compared in terms of changes in percentage of total sleep time spent in each stage, there were small decreases of ≤1%, ≤2.2%, and ≤0.8% for N1, N2, and N3/SWS on average, respectively, and an average increase of ≤3.9% in REM. The largest differences from placebo were observed at Night-1 and generally diminished over time. Suvorexant reduced REM latency (number of non-REM 30-s epochs from lights-off to the first REM epoch) compared with placebo; the reduction was greater at Night-1 (~40-50 non-REM epochs) in comparison to later time points (~12-25 non-REM epochs at Month-3). The spectral analysis of non-REM showed a small decrease in power of 3-6% in the gamma and beta bands, and a small increase of 4-8% in the delta band, at Night-1 for suvorexant relative to placebo; these effects were not apparent at the later Month-1 and Month-3 time points.

Conclusion: Overall sleep architecture appears to be preserved in insomnia patients taking suvorexant. The power spectral profile of suvorexant is generally similar to placebo.

Trial registration: ClinicalTrials.gov NCT01097616 NCT01097629.

Keywords: Orexin; Polysomnography; Power spectral density; Sleep architecture; Suvorexant.

Publication types

  • Clinical Trial, Phase III
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Azepines / therapeutic use*
  • Electroencephalography / drug effects*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Orexin Receptor Antagonists / therapeutic use*
  • Polysomnography / drug effects
  • Randomized Controlled Trials as Topic
  • Sleep Initiation and Maintenance Disorders / drug therapy*
  • Sleep Stages / drug effects*
  • Triazoles / therapeutic use*


  • Azepines
  • Orexin Receptor Antagonists
  • Triazoles
  • suvorexant

Associated data

  • ClinicalTrials.gov/NCT01097616
  • ClinicalTrials.gov/NCT01097629